In the construction of a motor vehicle various elements are made of hardened steel. The B-columns, for instance, are typically made of an extremely strong boron-alloyed steel having a tensile strength of about 1500 N/mm2. Such a part is produced by a complex manufacturing process and is-subsequently mounted on the motor-vehicle frame during the assembly of the vehicle.
A process is known from German patent 101 49 221 of Gehringhoff whereby an unhardened blank is formed with a rough bump or dimple that either constitutes a point at which an aperture is subsequently formed or that is a centering or mounting location used in the subsequent installation of the part. The dimpled unhardened blank is then fitted in a die and is simultaneously heat treated and deformed, and even if necessary punched out, so that the finished piece is hardened and has the exact end shape desired.
The problem with such parts is that when a repair has to be subsequently made it is extremely difficult or impossible to drill a hole through them to get at an underlying element. With a B-column, for example, screws holding up interior structure are covered by the B-column so that if subsequently the interior structure needs work, it is essentially impossible to get at these screws and do the necessary work. As a result the column has to be cut out, or the repair has to be conducted from inside, resulting in an unsatisfactory messy job.